Compression and deduplication layered driver

Abstract

A method, apparatus, and system for interposed file system driver is provided, which provides a logical file system on top of an existing base file system. One such interposed file system driver is a compression and deduplication layered driver (“COLD driver”). File system operations are intercepted from the operating system through the COLD driver, which is provided as an upper-level operating system driver that operates on top of an existing base file system. By processing file data through various modules, the existing base file system can be extended as a logical file system with compression, deduplication, indexing, and other functionality. The COLD driver can be implemented without requiring modifications to existing base file system structures or base file system drivers. Server deployments may thus leverage the additional file system functionality provided by the COLD driver without having to migrate to another file system.

What is claimed is: 
     
       1. A method comprising:
 invoking an interposed file system driver to request one or more operations on one or more logical files in a logical file system accessible via said interposed file system driver; 
 wherein said logical file system is associated with metadata stored in one or more specific base files in a base file system, wherein said metadata defines, at least in part,
 said logical file system, said metadata including a metadata mapping between logical files in said logical file system and base files in said base file system; 
 
 performing said one or more operations, wherein performing said one or more operations comprises:
 accessing said metadata mapping to determine that one or more base files are mapped to said one or more logical files; 
 accessing said one or more base files determined to be mapped to said one or more logical files; and 
 
 wherein the method is performed on one or more computing devices. 
 
     
     
       2. The method of  claim 1 ,
 wherein said one or more specific base files of said base file system are distinct files from said base files mapped to said logical files in said logical file system. 
 
     
     
       3. The method of  claim 1 , wherein said metadata stored in said one or more specific base files of said base file system is hidden from direct access by a user. 
     
     
       4. The method of  claim 1 , wherein said metadata stored in said one or more specific base files of said base file system is hidden from viewing by a user. 
     
     
       5. The method of  claim 1 , wherein performing said one or more operations further comprises translating said one or more base files according to said metadata mapping and storing one or more translated files into a buffer. 
     
     
       6. The method of  claim 1 , wherein said one or more operations includes a file operation request to delete said one or more logical files, and wherein performing said one or more operations further comprises:
 deleting said one or more base files determined to be mapped to said one or more logical files; and 
 deleting said metadata mapping that maps said one or more logical files to said one or more base files. 
 
     
     
       7. The method of  claim 1 , wherein said one or more operations includes a file operation request to move said one or more logical files, and wherein performing said one or more operations further comprises:
 updating said metadata mapping that maps said one or more logical files to said one or more base files to reflect said file operation request to move said one or more logical files. 
 
     
     
       8. The method of  claim 1 , further comprising:
 said interposed file system driver receiving a request for one or more operations on one or more base files in said base file system; and 
 forwarding said request for said one or more operations on said one or more base files to said base file system. 
 
     
     
       9. The method of  claim 1 , wherein said one or more operations includes a directory listing operation to display said one or more logical files within a directory, and wherein performing said one or more operations further comprises:
 displaying said one or more logical files and file attributes of said one or more logical files; and 
 wherein said file attributes of said one or more logical files includes a logical uncompressed file size of said one or more logical files. 
 
     
     
       10. A non-transitory computer-readable medium storing one or more sequences of instructions which, when executed by one or more processors, cause:
 invoking an interposed file system driver to request one or more operations on one or more logical files in a logical file system accessible via said interposed file system driver; 
 wherein said logical file system is associated with metadata stored in one or more specific base files in a base file system, wherein said metadata defines, at least in part,
 said logical file system, said metadata including a metadata mapping between logical files in said logical file system and base files in a base file system; 
 
 performing said one or more operations, wherein performing said one or more operations comprises:
 accessing said metadata mapping to determine that one or more base files are mapped to said one or more logical files; 
 accessing said one or more base files determined to be mapped to said one or more logical files. 
 
 
     
     
       11. The non-transitory computer-readable medium of  claim 10 ,
 wherein said one or more specific base files of said base file system are distinct files from said base files mapped to said logical files in said logical file system. 
 
     
     
       12. The non-transitory computer-readable medium of  claim 10 , wherein said metadata stored in said one or more specific base files of said base file system is hidden from direct access by a user. 
     
     
       13. The non-transitory computer-readable medium of  claim 10 , wherein said metadata stored in said one or more specific base files of said base file system is hidden from viewing by a user. 
     
     
       14. The non-transitory computer-readable medium of  claim 10 , wherein performing said one or more operations further comprises translating said one or more base files according to said metadata mapping and storing one or more translated files into a buffer. 
     
     
       15. The non-transitory computer-readable medium of  claim 10 , wherein said one or more operations includes a file operation request to delete said one or more logical files, and wherein performing said one or more operations further comprises:
 deleting said one or more base files determined to be mapped to said one or more logical files; and 
 deleting said metadata mapping that maps said one or more logical files to said one or more base files. 
 
     
     
       16. The non-transitory computer-readable medium of  claim 10 , wherein said one or more operations includes a file operation request to move said one or more logical files, and wherein performing said one or more operations further comprises:
 updating said metadata mapping that maps said one or more logical files to said one or more base files to reflect said file operation request to move said one or more logical files. 
 
     
     
       17. The non-transitory computer-readable medium of  claim 10 , storing additional instructions which, when executed by one or more processors, cause:
 said interposed file system driver receiving a request for one or more operations on one or more base files in said base file system; and 
 forwarding said request for said one or more operations on said one or more base files to said base file system. 
 
     
     
       18. The non-transitory computer-readable medium of  claim 10 , wherein said one or more operations includes a directory listing operation to display said one or more logical files within a directory, and wherein performing said one or more operations further comprises:
 displaying said one or more logical files and file attributes of said one or more logical files; and 
 wherein said file attributes of said one or more logical files includes a logical uncompressed file size of said one or more logical files.